[Elecraft] Battery power problems.

[Mark Schreiner]

Thomas,

I exclusively run my K2 with battery power (oh, I think I've used an 
Astron RS-20M on it once). I haven't had the problems you are 
experiencing just because it was run on a battery. Many times from out 
in the field I use smaller 7 AH gelcells (well, they are smaller than 
what I usually use as you'll see) when I put the rig, battery, antenna, 
etc in a backpack and go hiking to set up somewhere on the Appalachian 
Trail. These are the same batteries that are used in many UPS devices. 
When I'm home or where I can operate from a drive-up location for 
portable use I use the same type of battery, but it is in either an 18 
or 28 AH package in an automotive battery booster. I used one of those 
for the whole Field Day weekend last year without any problem at all on 
SSB. I've run the gelcells down to a reading of about 10.8 VDC at the 
radio during transmit at 5W, however the battery itself is still at 
about 11.8 VDC at 25% capacity at which time I swap out the booster pack 
for another fully charged one.

The only thing I did notice was that the el-cheapo cigarette lighter 
plug with small gauge wires definitely has more voltage drop than the 
heavier (and shorter) one I made up with 16 Ga wire. So, if voltage is 
at a premium I would opt for the cable I made up.

I doubt the problem is with the battery. Could be the wires from the 
battery to the rig causing excessive voltage drop. You also want to keep 
the RF away from the battery to rig wire, so don't wrap the feedline 
around the battery cable for example. I assume you're just running 5W 
since you didn't say you are running a K2/100, but this would be even 
more important at 100W.

73,

Mark, NK8Q
K2 4786

Thomas Beltran wrote:
> I ran my K2 last weekend on a battery (from my backyard – fully charged 52 Ah. Gel cell), and everyone on the net (40 meter SSB) complained that the signal was distorted and just plain sounded very bad.  One person suggested that it was the 12 volts put out by the battery, rather than the typical 13.8 volts.  I brought out my power supply and everything worked fine.  I guess it was surprising that this radio, that I understood was for portable operation wouldn’t work well on battery power.  Has anyone else experienced this or is it unique to my radio?  This is a 4000 serial number.  I have on order the W4RRY battery booster.  By comparison, my FT-857 seems unaffected by 12 volts.  Tom W6EIJ 
>
>  
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>
> Thomas E. Beltran, Esq.
> BELTRAN, BELTRAN, SMITH OPPEL & MACKENZIE, L.L.P.
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